User LEDs: Device or resource busy

Hi,

is it possible to achieve access to USR0 or USR1 LED on Beagleboard. When I try to make export file, I get:

-bash: echo: write error: Device or resource busy

It is because gpio-leds driver use it? The only way that it drop that pin is removing from kernel and recompilation?

Chhers
Valdez

Hi,

is it possible to achieve access to USR0 or USR1 LED on Beagleboard. When I
try to make export file, I get:
-bash: echo: write error: Device or resource busy

It is because gpio-leds driver use it? The only way that it drop that pin is

Yes, I think.

removing from kernel and recompilation?

No, I think. Have you tried:

     cd /sys/bus/platform/drivers/leds-gpio ; echo leds-gpio >unbind

Britton

Yes, using the leds-gpio driver, that gives you full control over it. incidentally, it's on by default

Valdez,

For most uses, you might find it easiest to just work with the driver. You can turn the LEDs on and off by writing to the file system.

Instructions and sample code for doing this can be found on various sites, like http://elinux.org/EBC_Exercise_10_Flashing_an_LED and http://www.lvr.com/beagleboard.htm.

Dan.

Hi,

is it possible to achieve access to USR0 or USR1 LED on Beagleboard.

Yes, using the leds-gpio driver, that gives you full control over it. incidentally, it's on by default

To be clear, you can control the LEDs either way: by using the already
loaded leds-gpio driver, or by unloading (unexporting, whatever) it
and then controlling that GPIO pin as normal.

I read some kernel documentation somewhere that said controlling the
LEDs with leds-gpio is the better way (if controlling LEDs is really
what you want). Not sure why.

Britton

This is exactly what I use: http://elinux.org/EBC_Exercise_10_Flashing_an_LED. I don’t have expansion header and my attempts to connect LED directly to the pads on board didn’t worked. But I wanted to try some things with GPIO, this is why I wanted to use LEDs on board, not just for control LEDs (what can be done by driver).

And it works:

`
cd /sys/bus/platform/drivers/
leds-gpio ; echo leds-gpio >unbind

`
After unbinding I have access to onboard LEDs :slight_smile:

Thanks Britton, Koen, Dan for all hints.

W dniu piątek, 21 września 2012 21:10:47 UTC+2 użytkownik valdez napisał: